configs: include the module call source range in our module tree

configs/config.go

@@ -35,6 +35,12 @@ type Config struct {
 	// various elements (variables, resources, etc) defined by this module.
 	Module *Module
 
+	// CallRange is the source range for the header of the module block that
+	// requested this module.
+	//
+	// This field is meaningless for the root module, where its contents are undefined.
+	CallRange hcl.Range
+
 	// SourceAddr is the source address that the referenced module was requested
 	// from, as specified in configuration.
 	//
@@ -50,7 +56,11 @@ type Config struct {
 	// Version is the specific version that was selected for this module,
 	// based on version constraints given in configuration.
 	//
-	// This field is meaningless for the root module, where its contents are undefined.
+	// This field is nil if the module was loaded from a non-registry source,
+	// since versions are not supported for other sources.
+	//
+	// This field is meaningless for the root module, where it will always
+	// be nil.
 	Version *version.Version
 }
 

configs/config_build.go

@@ -33,8 +33,9 @@ func buildChildModules(parent *Config, walker ModuleWalker) (map[string]*Config,
 			Name:              call.Name,
 			SourceAddr:        call.SourceAddr,
 			SourceAddrRange:   call.SourceAddrRange,
-			VersionConstraints: []VersionConstraint{call.Version},
+			VersionConstraint: call.Version,
 			Parent:            parent,
+			CallRange:         call.DeclRange,
 		}
 
 		mod, ver, modDiags := walker.LoadModule(&req)
@@ -50,6 +51,7 @@ func buildChildModules(parent *Config, walker ModuleWalker) (map[string]*Config,
 			Parent:          parent,
 			Root:            parent.Root,
 			Module:          mod,
+			CallRange:       call.DeclRange,
 			SourceAddr:      call.SourceAddr,
 			SourceAddrRange: call.SourceAddrRange,
 			Version:         ver,
@@ -110,12 +112,12 @@ type ModuleRequest struct {
 	// to a non-existent object, etc.
 	SourceAddrRange hcl.Range
 
-	// VersionConstraints are the constraints applied to the module in
+	// VersionConstraint is the version constraint applied to the module in
 	// configuration. This data structure includes the source range for
-	// each constraint, which can and should be used to generate diagnostics
+	// the constraint, which can and should be used to generate diagnostics
 	// about constraint-related issues, such as constraints that eliminate all
 	// available versions of a module whose source is otherwise valid.
-	VersionConstraints []VersionConstraint
+	VersionConstraint VersionConstraint
 
 	// Parent is the partially-constructed module tree node that the loaded
 	// module will be added to. Callers may refer to any field of this
@@ -124,4 +126,10 @@ type ModuleRequest struct {
 	// The main reason this is provided is so that full module paths can
 	// be constructed for uniqueness.
 	Parent *Config
+
+	// CallRange is the source range for the header of the "module" block
+	// in configuration that prompted this request. This can be used as the
+	// subject of an error diagnostic that relates to the module call itself,
+	// rather than to either its source address or its version number.
+	CallRange hcl.Range
 }